API Reference

Class List

XrTrackedImage

Extends: EventHandler

The tracked image interface that is created by the Image Tracking system and is provided as a list from XrImageTracking#images. It contains information about the tracking state as well as the position and rotation of the tracked image.

Summary

Properties

emulated

True if image was recently tracked but currently is not actively tracked due to inability of identifying the image by the underlying AR system.

image

Image that is used for tracking.

trackable

True if image is trackable.

tracking

True if image is in tracking state and being tracked in real world by the underlying AR system.

width

Width that is provided to assist tracking performance.

Methods

getPosition

Get the position of the tracked image.

getRotation

Get the rotation of the tracked image.

Events

tracked

Fired when image becomes actively tracked.

untracked

Fired when image is no more actively tracked.

Inherited

Methods

fire

Fire an event, all additional arguments are passed on to the event listener.

hasEvent

Test if there are any handlers bound to an event name.

off

Detach an event handler from an event.

on

Attach an event handler to an event.

once

Attach an event handler to an event.

Details

Properties

booleanemulated

True if image was recently tracked but currently is not actively tracked due to inability of identifying the image by the underlying AR system. Position and rotation will be based on the previously known transformation assuming the tracked image has not moved.

booleantrackable

True if image is trackable. A too small resolution or invalid images can be untrackable by the underlying AR system.

booleantracking

True if image is in tracking state and being tracked in real world by the underlying AR system.

numberwidth

Width that is provided to assist tracking performance. This property can be updated only when the AR session is not running.

Methods

getPosition()

Get the position of the tracked image. The position is the most recent one based on the tracked image state.

// update entity position to match tracked image position
entity.setPosition(trackedImage.getPosition());

Returns

Vec3

Position in world space.

getRotation()

Get the rotation of the tracked image. The rotation is the most recent based on the tracked image state.

// update entity rotation to match tracked image rotation
entity.setRotation(trackedImage.getRotation());

Returns

Quat

Rotation in world space.

Events

tracked

Fired when image becomes actively tracked.

untracked

Fired when image is no more actively tracked.

Inherited

Methods

fire(name, [arg1], [arg2], [arg3], [arg4], [arg5], [arg6], [arg7], [arg8])

Fire an event, all additional arguments are passed on to the event listener.

obj.fire('test', 'This is the message');

Parameters

namestring

Name of event to fire.

arg1*

First argument that is passed to the event handler.

arg2*

Second argument that is passed to the event handler.

arg3*

Third argument that is passed to the event handler.

arg4*

Fourth argument that is passed to the event handler.

arg5*

Fifth argument that is passed to the event handler.

arg6*

Sixth argument that is passed to the event handler.

arg7*

Seventh argument that is passed to the event handler.

arg8*

Eighth argument that is passed to the event handler.

Returns

EventHandler

Self for chaining.

hasEvent(name)

Test if there are any handlers bound to an event name.

obj.on('test', function () { }); // bind an event to 'test'
obj.hasEvent('test'); // returns true
obj.hasEvent('hello'); // returns false

Parameters

namestring

The name of the event to test.

Returns

boolean

True if the object has handlers bound to the specified event name.

off([name], [callback], [scope])

Detach an event handler from an event. If callback is not provided then all callbacks are unbound from the event, if scope is not provided then all events with the callback will be unbound.

var handler = function () {
};
obj.on('test', handler);

obj.off(); // Removes all events
obj.off('test'); // Removes all events called 'test'
obj.off('test', handler); // Removes all handler functions, called 'test'
obj.off('test', handler, this); // Removes all handler functions, called 'test' with scope this

Parameters

namestring

Name of the event to unbind.

callbackHandleEventCallback

Function to be unbound.

scopeobject

Scope that was used as the this when the event is fired.

Returns

EventHandler

Self for chaining.

on(name, callback, [scope])

Attach an event handler to an event.

obj.on('test', function (a, b) {
    console.log(a + b);
});
obj.fire('test', 1, 2); // prints 3 to the console

Parameters

namestring

Name of the event to bind the callback to.

callbackHandleEventCallback

Function that is called when event is fired. Note the callback is limited to 8 arguments.

scopeobject

Object to use as 'this' when the event is fired, defaults to current this.

Returns

EventHandler

Self for chaining.

once(name, callback, [scope])

Attach an event handler to an event. This handler will be removed after being fired once.

obj.once('test', function (a, b) {
    console.log(a + b);
});
obj.fire('test', 1, 2); // prints 3 to the console
obj.fire('test', 1, 2); // not going to get handled

Parameters

namestring

Name of the event to bind the callback to.

callbackHandleEventCallback

Function that is called when event is fired. Note the callback is limited to 8 arguments.

scopeobject

Object to use as 'this' when the event is fired, defaults to current this.

Returns

EventHandler

Self for chaining.